Technical Field
Embodiments generally relate to a belt device, a transfer device, and an image forming apparatus, and more particularly, to a belt device incorporating a belt, a transfer device for transferring an image., and an image forming apparatus for forming an image on a recording medium.
Background Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, and multifunction printers having two or more of copying, printing, scanning, facsimile, plotter, and other functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of a photoconductor; an optical writer emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device supplies toner to the electrostatic latent image formed on the photoconductor to render the electrostatic latent image visible as a toner image; the toner image is directly transferred from the photoconductor onto a recording medium or is indirectly transferred from the photoconductor onto a recording medium via art intermediate transfer belt finally, a fixing device applies heat and pressure to the recording medium bearing the toner image to fix the toner image on the recording medium, thus forming the image on the recording medium.
Such image forming apparatuses that form a toner image by electrophotography are not only used in offices but also used in home offices and by general users. In order to address usage in the home offices and by the general users, the image forming apparatuses are requested to form the toner image on transfer sheets of various types. To address this request, the image forming apparatuses may employ art intermediate transfer method. For example, after a toner image formed on the photoconductor is primarily transferred onto the intermediate transfer belt, a secondary transfer roller secondarily transfers the toner image from the intermediate transfer belt onto a transfer sheet.
In the intermediate transfer method, a coefficient of friction and an electric resistance of a driving roller that drives the intermediate transfer belt are adjusted. The coefficient of friction is adjusted to rotate the intermediate transfer belt precisely. If the coefficient of friction decreases, the driving roller idles and does not rotate the intermediate transfer belt. Conversely, even if the coefficient of friction increases, when a foreign substance such as toner adheres to a surface of the driving roller, the coefficient of friction of the driving roller decreases substantially.
The electric resistance is adjusted to enhance transfer performance to transfer the toner image from the intermediate transfer belt onto the transfer sheet.